Morphologic and biochemical information relating to critical events during gliogenesis is limited. The present proposal is designed to study neuroglial and neuronal factors that are likely to affect glial proliferation and differentiation. The present study will combine morphologic, autoradiographic and biochemical techniques to study these factors. Normal development and two experimental models of disease will be investigated. The two experimental models are the mouse mutant Jimpy which fails to form myelin in the Central Nervous System and malnourished animals which have reductions in the amount of myelin. The studies will use autoradiographic techniques to study and compare cell proliferation between the normal and experimental models. The biochemical studies will examine differences in the incorporation and uptake of components used in the manufacture of myelin.